Chest and back pain after running, with a sensation of fluid flowing inside the body—what could be the reason?

Chest and back pain after running, accompanied by a sensation of liquid flowing inside the body, may be caused by the following reasons:

1. Muscle fatigue or strain: During running, the muscles in the chest and back endure additional stress, which may lead to muscle fatigue, tension, or mild strain, causing pain. A mild sensation of increased blood flow may occur during muscle recovery after exercise.

2. Intercostal neuralgia: Strenuous exercise can sometimes compress or inflame the nerves between the ribs, resulting in sharp or burning pain, accompanied by a discomfort resembling a "flowing liquid" sensation.

3. Cervical spine issues: Herniation of the cervical intervertebral discs may compress nerve roots, causing nerve-related symptoms including chest and back pain.

4. Lactic acid buildup: If proper warm-up is not performed or the exercise is excessively intense, muscles may undergo anaerobic metabolism due to insufficient oxygen supply, leading to lactic acid production. Accumulation of lactic acid can irritate muscle tissues, causing pain in the chest and back areas.

5. Cardiovascular response: After high-intensity exercise, increased cardiac output and accelerated blood circulation may cause some individuals to feel a sensation of liquid flowing within the body. If accompanied by chest pain, it could indicate cardiovascular issues such as myocardial ischemia and should be taken seriously.

6. Digestive issues: Changes in blood supply to the gastrointestinal tract after exercise may cause acid reflux, leading to chest pain and discomfort.